Department of Neurology, Boston Children's Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, Massachusetts, 02115, USA.
Muscle Nerve. 2014 May;49(5):636-44. doi: 10.1002/mus.23967.
The purpose of this study was to measure and analyze motor unit number estimation (MUNE) values longitudinally in spinal muscular atrophy (SMA).
Sixty-two children with SMA types 2 and 3 were observed prospectively for up to 42 months. Longitudinal electrophysiological data were collected, including compound motor action potential (CMAP), single motor unit action potential (SMUP), and MUNE.
Significant motor neuron loss and compensatory collateral reinnervation were noted at baseline. Over time, there was a significant mean increase in MUNE (4.92 units/year, P = 0.009), a mean decrease in SMUP amplitude (-6.32 μV/year, P = 0.10), and stable CMAP amplitude.
The unexpected longitudinal results differ from findings in amyotrophic lateral sclerosis studies, perhaps indicating that compensatory processes in SMA involve new motor unit development. A better understanding of the mechanisms of motor unit decline and compensation in SMA is important for assessing novel therapeutic strategies and for providing key insights into disease pathophysiology.
本研究旨在测量和分析脊髓性肌萎缩症（SMA）中运动单位数量估计（MUNE）的纵向变化。
62 名 2 型和 3 型 SMA 患儿前瞻性观察长达 42 个月。收集了包括复合运动动作电位（CMAP）、单运动单位动作电位（SMUP）和 MUNE 在内的纵向电生理数据。
基线时观察到明显的运动神经元丢失和代偿性侧支再支配。随着时间的推移，MUNE 显著增加（4.92 个单位/年，P=0.009），SMUP 幅度平均降低（-6.32 μV/年，P=0.10），而 CMAP 幅度保持稳定。
出乎意料的纵向结果与肌萎缩侧索硬化症研究的结果不同，这可能表明 SMA 中的代偿过程涉及新的运动单位发育。更好地了解 SMA 中运动单位减少和代偿的机制对于评估新的治疗策略以及提供对疾病病理生理学的关键见解非常重要。
